1. Includes 257 shares acquired under the ALGN ESPP on January 31, 2018.

2. Represents par value of ALGN common stock.

3. 1/4th of the restricted stock unit granted on February 20, 2017 became vested on February 20, 2018 and shares were delivered to reporting person on such vest date. 1/4th of the restricted stock unit will continue to vest annually and shares will be delivered to reporting person on each vest date.

4. 1/4th of the restricted stock unit granted on February 20, 2018 will become vested on February 20, 2019 and shares will be delivered to reporting person on such vest date. 1/4th of the restricted stock unit will vest annually thereafter and shares will be delivered to reporting person on each vest date.

5. Represents the maximum number of shares which may be issued under the market stock unit. All of the shares which may be issued under the market stock unit will vest on the last day of the third year of the Performance Period (as defined in the market stock unit agreement).

Remarks:

Roger E. George Atty-In-Fact for John Morici

02/22/2018

** Signature of Reporting Person

Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person,
see
Instruction
4
(b)(v).